Total harmonic distortion is one of the critical specifications in safety standards in products associated with frequency converters, and a switching strategy is the mainly cause of effecting the harmonic distortion. A common frequency converter operates on a switching strategy of a pulse width modulator (PWM). The switching number and tracking accuracy of the modulator are positively correlated. In order to improve tracking accuracy, the switching frequency of the frequency converter is often increased, so that the system switching loss is increased.
Therefore, there is a need for switching strategy circuit having an enhanced system tracking accuracy without increasing the switching frequency.